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Topic: Lacto: Pure Culture or Malt Starter? (Read 2469 times)

I'm going to start brewing some sours this spring/summer (on purpose, for a change). Just wondering what people's experiences have been with growing up a culture from a small amount of malt, as opposed to ordering from one of the yeast labs. What are the odds of getting a Lactobacillus-dominated culture on the first try? Any issues with flavor stability over time? If I do get something I like I want to be able to store it in the fridge and reuse it at least a few times.

I haven't done it, but I know a pro brewer locally who sours his mash for some beers. He said it is really important to block out all of the air to keep it from getting nasty. That's not the first time I've heard that either, it seems to be a common belief.

The main trick is that lactobacillus grows best around 110F, so keep those cultures warm during growth. I've never heard of a sour mash going wrong, so I think it is pretty safe. Wort pH is probably low enough to at least inhibit most everything else until the lactobacillus gets going, which doesn't take long. Not sure about storage, but I imagine it would be stored like any other starter.

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Delmarva United Homebrewers - President by inverse coup - former president ousted himself.AHA Member since 2006BJCP Certified: B0958

Crooked stave acidfies their mash to a pH of 4.5 when doing sour mashes. I heard that on a podcast with the brewer.

IIRC, it sounded like the first time Chad sour mashed he ended up growing some butyric acid producing bacteria, and it took a really long time for the Brett to break it down to palatable levels. He started acidifying to pH 4.5 after that experience.

Another thing I remember is that lacto is active at temperatures above 125 F, but not much more while other beer bacteria generally are not. So it would be advantageous to pitch your grains say at 126 F and allow the wort to slowly cool to 110 F to give your lacto a head start.

Another thing I remember is that lacto is active at temperatures above 125 F, but not much more while other beer bacteria generally are not. So it would be advantageous to pitch your grains say at 126 F and allow the wort to slowly cool to 110 F to give your lacto a head start.

Lactobacilli have a generation time ranging from 25 to several hundred minutes. The optimal growth temperature ranges from 30 to 40°C, although some thermophilic strains grow well and have highly activated metabolism at temperatures around 45°C.

45C is 113F. Unless perhaps they will simply survive 125F while others will not.

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Delmarva United Homebrewers - President by inverse coup - former president ousted himself.AHA Member since 2006BJCP Certified: B0958

OK, I pitched a handful of crushed malt (Global Pils, FWIW) into a liter of 8.5°P wort, purged the growler with CO2 and sealed it with an airlock. It's in the fermentation chamber at 40°C. I guess we'll see what happens.